If you go this route, the key is to have all of the ground pins among the strips connected in common, but the +5V from each power supply should be connected only to one length of NeoPixels — those should not all be joined. Every power supply is a little different — not precisely 5 Volts — and this keeps some from back-feeding into others. | If you go this route, the key is to have all of the ground pins among the strips connected in common, but the +5V from each power supply should be connected only to one length of NeoPixels — those should not all be joined. Every power supply is a little different — not precisely 5 Volts — and this keeps some from back-feeding into others. |